High-density computer systems in which several tens to several hundreds of computer nodes are included in a single housing have recently been on the market. Such a computer system often includes a provisioning computer called a provisioning node. In general, a provisioning computer is not used commonly, but used as an alternative computer (alternative node) when the commonly-used computer fails. For this reason, it is necessary to carry out an operation of setting a boot image, which has been processed by the failed computer, as a boot image of the provisioning computer. If the provisioning computer is booted up after the setting, it can be used in place of the failed computer.
Tetsuo Kaneko and Yoshiya Mori, “Cluster Software,” Toshiba Review, Vol. 54, No. 12 (1999), pp. 18-21 (referred to as prior art document hereinafter) describes a computer system called a cluster system. In the cluster system, when a computer fails during operation, a service (business operation) that has been executed by the failed computer can be taken over to another computer in the system (fail-over). As the computer that took over the service, for example, a computer in a standby state (hot standby state) is used.
As described above, in the prior art computer system including a provisioning computer (provisioning node), when a computer in the system fails, the failed computer can be replaced with the provisioning computer. However, the prior art computer system requires an operator to replace the failed computer with the provisioning computer.
In the cluster system described in the above prior art document, a service that has been executed by a failed (troubled) computer can automatically be taken over to another computer in the system (fail-over).
In the cluster system, however, the computer to which the service is taken over needs to start up (boot up). It is thus difficult to apply a technique of taking over a service used in the cluster system to a mechanism capable of replacing a failed computer with a provisioning computer.